[GRASS-stats] gstat error

[Jarek Jasiewicz]

Edzer Pebesma pisze:
> Jarek Jasiewicz wrote:
>   
>> Hi
>> during trend calculation I recive following error:
>>
>> R
>> library(spgrass6)
>> library(gstat)
>>
>> raster=readRAST6("rzedna")
>> p=readVECT6("punkty")
>> p at proj4string=raster at proj4string
>>
>> pg_1=gstat(id="p_1", formula=rzedna~1,data=p, degree=1)
>> p_1=predict(pg_1,raster)
>> [ordinary or weighted least squares prediction]
>>
>> "solve.c", line 87: singular matrix in function Usolve()
>> Error in predict.gstat(pg_1, raster) : Usolve
>>     
> There are several situations why this can happen that are hard to
> distinguish from the point where the error happens. The most likely in
> your case (first order trend surface estimation) is that your data are,
> geographically, on a line, i.e. one-dimensionally. Or similary, that you
> have less than 3 observations. Is that the case?
> --
> Edzer
>   

Thanks for answer,  but none of that case. Tt is regular data file with 
200 random observations generated with v.random in GRASS and stored as 
SpatialPointDataFrame.
before I  posted to the list  I had tried to reproduce it on my archive 
data with archive scripts (which worked  in older R compilation) and it 
ALWAYS fail (on every data I tested).
 
In general, the possible problem on my side coud be that I 
(experientally) installed R from CRAN ubuntu repository instead to 
compile from source. The ubuntu CRAN-R packages do not include lapack. 
This is the only difference I noticed.

If you need I can send you sample R file (is small, no more than 2MB)

Jarek

>> my system information:
>>
>> Ubuntu 8.04
>> R 2.8.1
>> gstat 0.9.59
>> the error have appeared first time on gstat 0.9.49
>>
>> Errors apears on all my data, even these, where trend was calculated
>> some times ago. Commads coming from old data
>>
>> The error is also reproducible on spearfish dataset with elevation.dem
>> and random points generated by v.random
>>
>> Jarek
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>> http://lists.osgeo.org/mailman/listinfo/grass-stats
>>     
>
>